- A4.15 units
- B5.15 units
- C4.65 units
- D3.15 units
Step-by-Step Solution
, so the radius . Then units (and ).
Answer: A) 4.15 units
To locate √9.3, AB = 9.3 units and BC = 1 unit are marked on a line, O is the midpoint of AC, a semicircle is drawn on AC and BD is drawn perpendicular to AC. What is the length OB?
Class 9Number SystemsNumber Systems
Key idea: Representing real numbers on the number line
Every real number has a unique location on the number line.
- Rationals: easy to plot. → 3 quarters past 0.
- Irrationals like can be plotted geometrically: a right triangle with legs 1 and 1 has hypotenuse (Pythagoras). Use a compass to mark off on the number line from 0.
You can extend this — from a triangle with legs and 1, from legs 2 and 1, etc. (the spiral of Theodorus).
- Rationals: easy to plot. → 3 quarters past 0.
- Irrationals like can be plotted geometrically: a right triangle with legs 1 and 1 has hypotenuse (Pythagoras). Use a compass to mark off on the number line from 0.
You can extend this — from a triangle with legs and 1, from legs 2 and 1, etc. (the spiral of Theodorus).
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